1. Field of the Invention
Aspects of the present invention relate to computing systems. More particularly, aspects of the present invention relate to a process for determining when a hand-written gesture has occurred.
2. Description of Related Art
Computing systems accept a variety of inputs. Some computer applications accept gestures formed by pointing devices to enable easier control and navigation of the applications. The difficulty however with conventional gesture recognizers is that they provide too many false positives and false negatives. When a user is using a pointing device (for instance, a stylus or finger with a stylus-based computer or a mouse), a system may interpret normal actions from the pointing device as gestures and implement the functions associated with the gestures to the bewilderment of the user. Likewise, a user may become frustrated when trying to perform a gesture and the computing system not recognizing the user's effort as a gesture. In some cases, gestures are relegated to a separate operation where a user is forced to change a mode of a system before a gesture may be recognized. For instance, the Opera browser (by Opera Software ASA of Oslo, Norway) permits mouse gestures to be used to control the browser's operation. Similar mouse gestures are available through plug-ins with the Firefox browser (by the Mozilla Organization, Mountain View, Calif.). While these browsers recognize gestures, the user is required to switch operating modes of the browsers in order to explicitly notify the browsers that gestures are to be performed. In both the Opera and Firefox browsers, the operating mode is switched by the user clicking on a right (or auxiliary) mouse button prior to performing the gesture. The issue here is that multiple steps have to be performed in order to complete all gestures, namely press a right mouse button and then drag the mouse. When using a stylus, these browsers require the stylus to enter an alternative input mode, namely pressing a stylus button (if the stylus has a stylus button). These multiple steps make gestures cumbersome. Further, while these browsers may recognize a gesture composed of a straight line while depressing a mouse or stylus button, gestures acceptable on browsers are generally not usable in more environments because they would generate too many false positives when applied to non-read only environments (for instance, a word processing environment).
In computer systems or computer applications that recognize and assign functions to gestures, shape alone is generally used to determine whether or not a gesture has occurred. An issue with using shape alone is that slow stylus or mouse-wielding users may have a tendency to perform actions that may be recognized as gestures, despite the intentions of the users to the contrary.
Marking menus (also referred to as radial menus) are menus that may be accessed through interaction with a pointing device. Maya and Alias applications of Alias Systems Corp. of Toronto, Ontario, Canada provide examples of marking menus. While similar to gestures in that they include start and stop locations, marking menus are considered menus in that the relevant part of the user input is the location of a button up or stylus up event, not the shape of the actual path to the location.
An improved gesture is needed that is easily recognized by a gesture recognizer yet easy to perform by a user.